When a substrate, which is in a shape of a band or the like, is continuously coated with a paste-like coating material while the substrate is conveyed, there are some cases where it is necessary to accurately adjust a weight (that is, a coating weight) per unit area of the coating material attached to the substrate. For example, in a battery sheet electrode manufacturing apparatus, since a weight per unit area of an electrode active material with which a collector sheet as a substrate is coated affects performance of a secondary battery, it is necessary to accurately adjust the weight per unit area of the electrode active material. In view of the quality of a secondary battery, it is important to match coating end positions of the electrode active material with which both the front and rear surfaces of the substrate are coated with each other. Accordingly, it is necessary to accurately adjust the coating end positions. From the viewpoint of productivity, it is necessary to match the coating end position with a set value for a time as short as possible from a start of the coating.
For example, Patent Literatures 1 to 3 describe a coating machine which includes a backup roll supporting a substrate and a die coater disposed opposite to the backup roll so as to eject an electrode active material and which adjusts an amount of electrode active material ejected by adjusting a rotation speed of a pump pressure-feeding the electrode active material to the die coater or a gap between the die coater and the substrate and thus adjusts a weight (that is, a coating weight) per unit area of the electrode active material to match a set value.
Patent Literatures 1 to 3 describe adjustment of the coating weight, but fails to describe, for example, adjustment of the rising profiles of ends of the electrode active material in a substrate width direction or the profile of a central region between the ends. That is, a technique of focusing on a surface profile in a substrate width direction of a coating material such as an electrode active material and adjusting to optimize the surface profile has not been proposed yet.
In order to achieve further improvement in the performance of a secondary battery, it is considered that it is necessary to adjust coating conditions including a coating weight of an electrode active material and end positions thereof with higher accuracy. Accordingly, there is necessity for adjusting coating conditions of a coating material including the surface profile thereof.